Application of image analysis for thermal fatigue heat checking investigations
Résumé
Surface cracking or heat-checking (HC) is investigated on a hot work tool steel (X38CrMoV5 - AISI H11). Different thermal fatigue (TF) test conditions are examined. A semi-automatic and non-destructive investigation method is developed in order to describe the microscopic crack patterns formed on the oxidized specimen surface. TF experiments are periodically interrupted to observe the specimen’s surface with scanning electron microscopy. Crack patterns are evaluated by image analysis. The density and geometrical properties of HC at different stages are characterised. Topological properties of the crack networks are also investigated.